1 Answer
1

There are a few opinions in the literature (see Fassberg's paper on the lengthened imperative which has a huge number of excellent references). A summary of the opinions presented looks more or less as follows:

None

Emphasis (paralleled to the Arabic), similar to the cohortitive meaning

Emphasis originally, although the distinction became more stylistic than functional

Euphony

Used as a polite/honorary form, respecting the subject (usually God or a priest etc.), potentially meaning "please"

The insightful opinion of Fassberg himself, that the lengthened imperative is used when the action (i.e. the result) or object of the imperative is of interest or closely related to the speaker, or if the speaker will partake in that particular action (which is then often followed by the 1st person plural cohortative)

@bjorne thanks for this answer. Could you edit the links from your comment into the post itself? (Comments can have a shorter lifespan on Stack Exchange than posts themselves.) Thanks.
–
Gone QuietAug 12 '13 at 22:02